Watching you itch makes me itchy

You know how seeing someone scratching an itch makes you feel itchy too? That's perfectly normal, a new study says, especially for those who tend to be on the neurotic side.

Research published online in the Proceedings of the National Academy of Sciences has offered evidence of the neurotic basis of contagious itch. In the study, conducted in Britain, 51 healthy adults watched videos of people either scratching parts of their upper bodies or merely tapping those areas with their fingers.

The participants reported whether they felt an urge to scratch — and, if so, how strong it was — when viewing each video. The volunteers also were videotaped as they watched, so the researchers could document how often they actually scratched themselves.

A big majority, 64 percent, scratched themselves at least once while watching images of others scratching themselves. And while participants scratched themselves during both sets of videos, most of the scratching (59.5 percent, or 132 scratches) took place while or just after people viewed a scratching video; 90 scratches occurred in association with the tapping videos. This indicates that itching may be more "socially contagious" than yawning (which 40 to 60 percent of people will do when they see someone else yawn, other research has found) and laughing (47 percent), the study notes.

MRI scans of participants' brains also revealed that seeing someone scratch triggers activity in the parts of the brain that are activated when a person has an itch.

Alas, it is apparently not empathy that makes us share the urge to scratch. It is neuroticism. People in the study whose personality profiles included a high degree of that trait were more likely than less neurotic participants to report feeling itchy when watching others scratch.